sequence ? hardie, tar paper, flashing
I want to reside a small dormer (that sticks up thru a roof of course) with hardie plank horizontal siding
My question is about the tar paper/step flashing overlap sequence.
First I rememove the wood siding.
starting with the inner most layer, which is the existing sheathing of the dormer, the next layer will be the new tarpaper. then the hardie
AT THE BOTTOM (intersection with the roof) where does the tarpaper go: ???
1. between the existing asphalt shingles aluminum step flashing and the sheathing? This sequence is sheathing, then tar paper, step flash, hardie. Seems this would funnel water that runs down the tar paper into the area behind the step flashing
or
2. At the bottom, Let tar paper lay outside of the step flashing – so that the sequence coming off the sheathing (at the bottom) is sheathing, then vertical edge of the flashing, then tar paper (lapping over the step flashing) then hardie. This method allows for proper water run down but if you ever replaced the shingles seems it would be hard working the step flashing up under the tar paper edge.
seems like #2 is the way?
Thanks
Replies
work from the bottom ...
think like water.
#2.
Jeff
Buck Construction, llc Pittsburgh,PA
Artistry in Carpentry
When you re-roof, it's usually necessary to remove the bottom course of siding at roof-to-wall junctions, if you are going to replace the flashing. The flashing is behind the paper which is behind the siding, and there's usually no choice but to remove and replace/re-install some siding... but it's easier than replacing the ceiling plaster inside!
this is a slanted dormer/roof intersection (as all are) so you would have to take off all the horizontals - thats why i asked
thanks
The right way is to strip the whole thing, reflash, repaper, reside. In my opinion, builders are pretty much defined by how well they know how to keep out water.
You might also try punching the nails through to pull the old flashing instead of removal.
When you've either stripped the siding off or worked with it in place you should ensure that there is a 1-1.25 gap (measured square to the roof) from shingles to siding. This will allow the next flashing job to go easier and also keep water from rotting the ends of the claps.
If the siding is left in place you could probably use a skil saw to trim it up.
Jon Blakemore
Thanks on the gap
No rot with hardie plank
yup ...
hold it up too ... good point.
Jeff
Yeah number 2--the fact that the paper is over the flashing is far more benenifial than the other way --the water running down the roof would have to pile up the hieght of the flashing ( and thats like 4 inchs right) in order for the water to get into the joint between the roof and the dormer wall . Mike